Safety-valve.



Patented Feb 1, 1916 5 SHEETS-SHEET l.

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SAFETY VALVE APPLICATION FILED Aue. 14. 1914.

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SAFETY VALVE.

APPLICATION FILED Aue.I4, I9I4..

1,169,926. Patented Feb. 1, 1916.

5 SHEETS-SHEET 2.

THE COLUMBIA PLANDGRAPH co.. WASHINGTON, D. c.

D. COCKBURN & D. MAcNICOLL.

SAFETY VALVE.

APPLICATION FILED AUG. I4. 1914.

Patented Feb. 1, 1916.

5 SHEETS-SHEET 3.

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D. COCKBURN & D. MACNICLL.

SAFETY VALVE.

APPLICATION FILED 11116.14, 1914.

Patented Feb. 1, 1916.'

5 SHEETS-SHEET 4 THE COLUMBIA PLANQGRAPH co.. WASHINGTON. D. c.

D. COCKBURN & D. MACNIGOLL.

SAFETY VALVE. APPLICATION FILED lAUG. I4, 1914.

Patented Feb. 1, 1916.

5 SHEETS-SHEET 5.

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DAVID COCKBURN AND DONALD MACNIOOLL, OF CARDONALD, NEAR GLASGOW,

SCOTLAND.

SAFETY-VALVE.

Application filed August 14, 1914.

To all whom t may concern.'

Be it known that we, DAVID COCKBURN and DONALD MAONICOLL, subjects of the King of the United Kingdom of Great Britain and Ireland, and residents of Cardonald, near Glasgow, Scotland, have invented a certain new and useful Improvement in Safety-Valves. of which the following is a specification.

This invention relates to safety valves of the type including a main valve and a pilot valve, the opening of which pilot valve, under normal conditions, results in the automatic opening of the main valve.

Now, the `present invention provides means whereby the main valve may be opened-positively without altering the position of the pilot valve.

In the accompanying drawing Figure 1 is a side elevation. Fig. 2 a plan of a safety valve embodying the invention. Fig. 3 is a vertical section drawn through the valve. Fig. e is a side elevation of the valve on a reduced scale from that shown in the remaining figures of the drawings. Fig. 5 is an irregular horizontal section drawn on the line z-a of Fig. 3. Fig. 6 is a vertical transverse section drawn on the irregular line b-b of Fig. 5.

Referring to the drawing, `1 denotes the spindle of the pilot valve l which serves under normal conditions to control the main valve 2, said valve spindle l receiving. actuation from a lever 3 fulcrumed on the valve casing at 4 and coperating with a cam element 5 keyed to a rock shaft 6 on which shaft 6 is a tappet arm 7 arranged in operative relationship with the main valve. On initial movement of the shaft 6 the cam element 5 engages the coperating arm of the said lever 3 and acts to tilt said lever so that the end 8 of the short arm of said lever engages a shoulder 9 on the spindle 1 of the pilot valve and thereby opens said pilot valve. Under normal conditions, when the pilot valve is opened, the main valve opens automatically under the influence of steam pressure controlled by said pilot valve; if, however, the main valve fail to open automatically either by reason of the absence of Specification of Letters Patent.

Patented Feb. 1, 1916.

serial No. 856,823.

steam pressure or as a result of adhesion of the main valve stem to its guide, then, on continued movement of the shaft 6, the tappet arm 7 engages the main valve 2 and opens the same positively. As will be evident from the drawing, the cam element 5 in participating in the further movement of the shaft G does not affect the coperating lever 3, the position of the pilot valve being thereby unaltered.

The rock shaft 6 is provided at one end with a crank arm 10 to the free end of which is pivoted one end of a connecting rod 11 extending to within convenient reach of the operator.

Having now described our invention what we claim and desire to secure by Letters Patent of the United States is l. In a safety valve, in combination, a main valve, a separate pilot valve normally adapted when open to effect the automatic opening of said main valve, and manually operable means including a rock-shaft adapted in the first part of the rocking movement thereof to effect the positive opening of said pilot valve and thereafter on further movement of said shaft to effect the positive opening of said main valve without further displacement of said pilot valve.

2. In a safety valve, in combination, a main valve, a pilot valve adapted when open to effect the automatic opening of said main valve, and a train of connections for effecting successively the 4positive opening of said pilot valve and of said main valve, said train of connections including an interponent which when moved into one position acts to open the pilot valve, and when moved to a position at which the main valve is opened acts to maintain the pilot valve in open position so that any movement of the main valve eected by action of the pilot valve or by the train of connections has no effect on the pilot valve.

3. In a lsafety valve, a pilot valve, a main valve, means including a cam element and a coperating lever for transmitting movement to said pilot valve, and a tappet arm adapted for direct cooperation with the main valve, said cam element and lever and said tappet arm being adapted to act sucnames to this specification in the presence cessively, said tappet arm acting on the of two subscribing Witnesses.

main valve after the action of the @am ele- DAVID COCKBURN. ment and lever on the pilot valve, and only DONALD MACNICOLL. a' in case of failure of the main valve to open l/Vitnesses: l

automatically. JAMESRODGER,

In testimony whereof We have signed our D. K. HAMILTON.

Copies of this patent may be obtained for five cents each, by r:mddrziessng the Commissioner of Patents,y Washington, D. C. 

